Aqueous grow chamber recirculating nutrient control system and sensor calibration

Abstract

An aquaponic grow system includes a plurality of sensors for sensing nutrient levels in liquid provided to a grow chamber, and to adjust nutrient levels based on the sensed levels. In some embodiments the system includes a plurality of sensors configured to sense nutrient levels in a common chamber, with the system configured to calibrate the sensors.

What is claimed is: 
     
       1. A nutrient control system for aquaponically grown plants, comprising:
 a grow chamber for aquaponically growing plants; 
 a liquid solution line for providing liquid solution to the aquaponically growing plants and for receiving liquid solution from the aquaponically growing plants, so as to recirculate the liquid solution; 
 a plurality of nutrient tanks containing nutrients coupled to the liquid solution line; 
 a plurality of reference solution tanks containing reference solutions; 
 a chamber selectively coupled to the liquid solution line and to the reference solution tanks, the chamber including an inlet port for passage of solution into the chamber and an outlet port for passage of solution out of the chamber, the output port having a reduced diameter compared to a diameter of the inlet port; 
 a plurality of sensors for sensing ion levels in solution in the chamber; 
 a controller configured to control addition of the nutrients to the liquid solution based on sensed ion levels in solution in the chamber, configured to perform sensor calibration based on sensed ion levels in solution in the chamber, and to selectively couple the chamber to the liquid solution line or to the reference solution tanks; and 
 a plurality of isolation amplifiers coupling the plurality of sensors and the controller. 
 
     
     
       2. The system of  claim 1 , wherein the controller is further configured to selectively couple the reference solution tanks to the chamber at different times. 
     
     
       3. The system of  claim 2 , wherein the controller is configured not to perform sensor calibration during times at which the chamber is coupled to the liquid solution time and to perform sensor calibration during times at which the chamber contains at least one reference solution. 
     
     
       4. The system of  claim 1 , further including a plurality of valves, at least one of the valves for selectively coupling the chamber to the liquid solution line and the reference solution tanks. 
     
     
       5. The system of  claim 4 , wherein the controller is configured to control the valves. 
     
     
       6. The system of  claim 1 , wherein the sensors comprise ion sensing electrodes. 
     
     
       7. The system of  claim 6 , wherein at least some of the ion sensing electrodes are configured to sense different ions. 
     
     
       8. The system of  claim 1 , wherein different ones of the reference solutions comprise solutions with different levels of ions. 
     
     
       9. The system of  claim 8 , wherein at least some of the reference solutions comprise solutions with different levels of a plurality of ions. 
     
     
       10. The system of  claim 1 , wherein at least one of the reference solution tanks contains a cleansing solution. 
     
     
       11. The system of  claim 1  wherein the grow chamber includes one or more vertical walls for mounting of plants for aeroponic growth. 
     
     
       12. A method for control of nutrients provided to aquaponically grown crops, comprising:
 recirculating a liquid solution containing nutrients through an aquaponic grow chamber; 
 sensing levels of a plurality of ions in the liquid solution containing nutrients using a plurality of sensing devices having portions immersed in a single chamber, the single chamber having an inlet port and an outlet port, the outlet port having a reduced diameter compared to a diameter of the inlet port, the sensing devices coupled to a controller by isolation amplifiers; 
 determining, by the controller, that at least one of the sensing devices indicates a selected ion level below a predetermined selected ion level; 
 responsive to the determination that at least one of the sensing devices indicates the selected ion level below the predetermined selected ion level, commanding, by the controller, an increase in a selected nutrient; 
 responsive to the command by the controller to increase the selected nutrient, increasing a quantity of the selected nutrient in the liquid solution containing nutrients; 
 providing a plurality of reference solutions to the single chamber, each of the plurality of reference solutions being provided to the single chamber at different times; 
 sensing levels of the plurality of ions in the reference solutions using the plurality of sensing devices; and 
 generating calibration curves for the sensing devices, by the controller, using indications of the sensed levels of the plurality of ions in the reference solutions. 
 
     
     
       13. The method of  claim 12 , further comprising controlling a plurality of valves to control provision of the liquid solution containing nutrients or the reference solutions to the single chamber. 
     
     
       14. The method of  claim 13 , wherein the controller controls the plurality of valves. 
     
     
       15. The method of  claim 12 , wherein at least some of the reference solutions contain different predetermined levels of the same ion. 
     
     
       16. The method of  claim 12 , wherein at least some of the reference solutions contain different predetermined levels of a plurality of ions. 
     
     
       17. The method of  claim 12 , wherein the sensors comprise ion selective electrodes. 
     
     
       18. The method of  claim 17 , wherein at least some of the ion selective electrodes are configured to sense levels of different ions. 
     
     
       19. The method of  claim 18 , wherein at least some of the ion selective electrodes are configured to sense levels of a same ion.